Photoflash projection device and a method of using the device

Abstract

A Photoflash Projection Device and a method of use includes a linear discharge tube in an elongated concave reflector, powered by a self-contained multiplying circuit. The reflector, having a predetermined shape to include a Natural Log Function, novelly projects and spreads a uniform light density over a wideangle/graduated depth area. This permits a user to direct light above the field's rearground to achieve the ideal photographic illumination. The flash unit further includes a support stand mounting bracket that is adjustable relative to the base of the housing. The invention is particularly suited for large Group/Commercial photography.

I claim:  
     
       1. A photoflash projection device comprising: 
       a housing defining an interior space and having an exterior surface;  
       a multiplying circuit for receipt into the interior space of the housing; and  
       a lamp, the lamp for engaging the housing and multiplying circuit, the lamp comprising:  
       a straight, elongated, glass, gas-containing, flash discharge tube having a first end and second end, the two ends engaged in gas sealing relation by two electrodes;  
       a reflector surface, the reflector surface adjacent and parallel to the straight flash discharge tube, the reflector surface having a profile defining a natural log function in a plane with a longitudinal axis of the reflector surface parallel to the longitudinal axis of the tube the profile between a maximal profile defined by Y=8.98 LN (X−6)+2.34 and a minimum profile defined by Y=5.58 LN(X−6)+1.30; and  
       a pair of side reflector plates located at two removed ends of the reflector surface, whereby said multiplying circuit engages the tube to intermittently apply a potential difference across the electrodes of the tube sufficient to create a flash discharge therefrom.  
     
     
       2. The device of  claim 1  wherein the gas in the flash discharge tube is xenon. 
     
     
       3. The device of  claim 2  wherein the xenon is at a pressure of about 165 mm of pressure against atmospheric pressure. 
     
     
       4. The device of  claim 2  wherein the xenon is at a pressure of between 30 and 300 mm pressure against atmospheric pressure. 
     
     
       5. The device of  claim 1  wherein the length of the flash discharge tube is between 20.3 and 45.6 centimeters long. 
     
     
       6. The device of  claim 1  wherein the flash discharge tube is about 26.5 cm long and has a outside diameter of about 8 millimeters and is located a distance of 1.10 cm from an apex of the reflector surface. 
     
     
       7. The device of  claim 1  wherein the reflector surface has a length, at a mouth thereof of between 23.0 and 46.0 centimeters and a width at the mouth thereof of the between 5.2 and 9.2 centimeters and depth of between 4.5 and 10.0 centimeters. 
     
     
       8. The device of  claim 1  wherein the reflector surface has a length of about 30.0 centimeters, width of about 6.7 and a depth of about 5.8 centimeters. 
     
     
       9. The device of  claim 1  wherein the reflector surface has a length of about 30.0 centimeters, width about 6.7 centimeters and depth of about 5.8 centimeters, and wherein the flash discharge tube is filled with xenon gas, and wherein the flash discharge tube is about 26.5 cm long and about 8 millimeters in diameter, and is located a distance of about 1.10 cm from an apex of the reflector surface. 
     
     
       10. The device of  claim 1  wherein each of the pair of side reflector plates intersects at an angle between 10 degrees and 40 degrees with a plane perpendicular to a longitudinal axis of said flash discharge tube. 
     
     
       11. The device of  claim 9  wherein each of the pair of side reflector plates intersects at an angle between 10 degrees and 40 degrees with a plane perpendicular to a longitudinal axis of the flash discharge tube. 
     
     
       12. The device of  claim 9  wherein the side reflector plates intersect at an angle of about 25 degrees with a plane perpendicular to a longitudinal axis of the flash discharge tube. 
     
     
       13. The device of  claim 1  wherein the multiplying circuit is capable of a discharge of 800 watt-seconds of energy. 
     
     
       14. A lamp for use in a photoflash projection device having a housing and a multiplying circuit, the lamp comprising: 
       a straight elongated, glass, gas-containing, flash discharge tube having a first end and second end, the two ends engaged in gas sealing relation by two electrodes;  
       a reflector surface, the reflector surface adjacent and parallel to the straight flash discharge tube, the reflector surface having a profile defining a natural log function in a plane with a longitudinal axis of the reflector surface parallel to a longitudinal axis of the tube the profile between a maximal profile defined by Y=8.98 LN (X−6)+2.34 and a minimum profile defined by Y=5.58 LN(X−6)α1.30; and  
       a pair of side reflector plates located at two removed ends of the reflector surface whereby the multiplying circuit engages the tube to intermittently apply a potential difference across the electrodes of the tube sufficient to create a flash discharge therefrom.